Cold boot to i3 and launch Alacrity:

  bash-5.1$ uptime
  08:38:18 up 1 min,  1 user,  load average: 0.18, 0.06, 0.02
  bash-5.1$ free -m
         total        used        free      shared  buff/cache   available
  Mem:   63997         674       61498         129        1824       62579
  Swap:  8191           0        8191
  bash-5.1$ cat /etc/fedora-release
  Fedora release 35 (Thirty Five)

Purely anecdotal - i3 + picom idles around 350MB while tiling wayland compositors (sway/hyprland) idle closer to 500MB

Arch, i3, RSS sizes, only counting processes from logged-in user:

2.6 GB ungoogled-chromium (Browser) 150 MB kitty (Terminal) 50 MB udiskie (Automounter) 46 MB picom (Compositor) 36 MB pulseaudio (Sound) 26 MB gpaste-daemon (Copy Paste) 21 MB polybar (Bar on top of screen) 20 MB dunst (Notifications) 17 MB i3 (WM itself)

Plus a bunch of services below that, which at this point is only noise. If palemoon works for you as a browser, that will only use 320 MB RSS empty on startup.

Machine has 64 GB RAM, no idea if Chromium by design would eat less on less beefier machines. At 4 GB RAM, zRAM is certainly an option, if you can't or don't want to upgrade. Without such tweaking, modern Linux desktops profit from 8 GB RAM. No matter what WM or DE you run. Once you start a web browser, game over. ;-)

I've run sway on most of my home hardware for 2-3 years which ranges from i7 4 core to Ryzen 4700 8 core with 16 GB RAM and all of my post-boot measurements hover in the 512-640 MB range.

I'm usually on arch but these numbers seem consistent from debian to fedora to arch. Sway deserves credit for managing IPC latency like a cloud provider manages RPC latency.

I miss the days when personal computers were near zero latency but sway is as good as it gets in that regard, which is why I'm a fan. There's a lot to learn from the sway design.

I guess they are similar to what IceWM shows.